Figure 3.

Amino acid export sensitivity to inhibitors of the proton gradient or ATP hydrolysis. Wild-type (WT) and gdu1-1D plants were pretreated with dimethyl sulfoxide (DMSO), 100 μm CCCP, 100 μm DNP, 1 mm VO₄, and 100 μm DES. The same amount of dimethyl sulfoxide was present in each sample. Uptake was performed for 10 min in the presence of 5 mm Phe; plants were allowed to release radioactivity for 10 min in the same medium without Phe. A, Total Phe taken up. DW, Dry weight. B, Percentage of Phe present in the medium after the efflux experiment, expressed as a percentage of the total Phe taken up. Means ± se of three biological replicates are shown. Significant differences from the wild type (t test) are as follows: * P < 0.05, ** P < 0.01.